<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .container{
            width: 300px;
        }
        .pull-left{
            float: left;
            
        }
        .box0{
            width: 200px;
            height: 200px;
            background-color: lightblue;
        }
        .box1{
            width: 100px;
            height: 100px;
            background-color: tomato;
            z-index: 2;
        }
        .box2{
            width: 100px;
            height: 100px;
            background-color: lightcyan;
            z-index: 3;
        }
    </style>
</head>
<body>
    <div class="container">
        <div class="pull-left box0"></div>
        <div class="pull-left box1"></div>
        <div class="pull-left box2"></div>
    </div>

    <div></div>
</body>
</html>